Head-block shifter for sawmills.



, No. 758.337. PATENTED APR. 26; 1904.

v J. T. SIMPSON. HEAD BLOCK SHIFTBR FOR sAwMILLs.

APPLICATION FILED JAN. 30, 1904.

N0 MODEL.

mi hwaaco I To all whom it may concern.-

Patented April 26, 1904.

UNITED STATES PATENT OFFICE.

JOHN T. SIMPSON, OF LOUDON, TENNESSEE.

HEAD-BLOCK SHIFTER FDR SAWMILLS- SPECIFICATION forming part of Letters Patent N0. 758,337, dated April 26, 1904. Application filed January 30, 1904. Serial No. 191,367. (No model.)

Be it known that I, J OHN T. SIMPSON, a citizen of the United States, residing at London, in the county of London and State of Tennessee, have invented certain new and useful Improvements in Head-Block Shifters for Sawmills; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

The object of my invention is to provide simple and efficient means for shifting by power the head-blocks of sawmills longitudinally of their carriages for the purpose ofadjusting the distances between the head-blocks to ac commodate logs of different lengths. This is accomplished by means substantially as illustrated in. the accompanying drawings, where- 111- Figure l is a perspective view of an ordinary sawmill having my invention applied thereto, and Fig. 2 is a detail side view of the shifting device.

In said drawings, A designates the carriagetrack. B denotes the carriage, and C and D I denote the head-blocks.

The mechanism shown for imparting the necessary feed and gig-back motions to the carriage, as well as the device for settingup the knees of the head-blocks closer to the saw after each cut, are of well-known construction, and hence a specific explanation is deemed unnecessary.

Either one or both of the head-blocks can be shifted longitudinally of the carriage to alter the distance between the two head-blocks, though such adjustment is generally made by moving one head-block only. The old way of doing this is bytwo men with pries working at opposite ends of thehead-block which it is desired to shift. By my present invention this can be accomplished easily and quickly by the power which runs the mill.

My improved shifter consists of a device which normally stands out of the way of the head-block, but is adapted to be thrown into ing its position on the carriage. In the construction illustrated the shifting device com prises an upstanding rod or bar E, secured between two braces F, which are pivoted in a bracket Gr, secured to the sides of the carriagetrack. The device can thus be rocked from upright toinclined position, and vice versa.

The lower end of the rod or bar E is shown connected by a rod H to an arm J on an upright rod K, having a hand-lever L, whereby the operator can easily throw the device from one position to another. Said rod E is also shown bent or angular, so that its upper part rests against the carriage when the device is moved to upright position, while its lower part rests against the carriage-track when the device is thrown to inclined position, thus limiting the movement of said device. These details of construction and arrangement may be changed, however, without departing from the scope of my invention.

When the shifting device is in inclined position, as shown in dotted lines, its top stands out of the way of the headblocks,which thus pass over it as the carriage reciprocates. Now when it is desired to alter the distance between the two head-blocks this is performed as follows: Suppose, for example, the rear head-block C is to be shifted. If it is to be moved nearer to the front head-block, the shift ing device is thrown to upright position while the head block C is in front of it, as shown in full lines, so as to engage'and stop said headblock C when the carriage travels backward, (or, looking at the drawings, toward the observer,) and thus when the carriage stops or when the shifter is again thrown to inclined position, both at the will of the opera ator of course, said rear head-block'has a position nearer the front head-block. If it is desired to move the rear head-block farther from the front headblock, the shifter is brought to position to engage it at its other side on forward travel of the carriage. Either Having thus fully described my invention, what I claim as new, and desire to secure by Letters Patent of the United States, is-

1. In a sawmill, the combination with the log-carriage having a longitudinally-movable head-block, of a head-block shifter consisting of a stop adapted to be moved into and out of the path of travel of the head-block at will, substantially as described.

2. In a sawmill, the combination with the log-carriage having a longitudinally-movable head-block, of a head-block shifter consisting of a stop pivotally secured to a fixed support so as to move transversely to the carriage and capable of being thrown into and out of the path of travel of the head-block at will, substantially as described.

3. In a sawmill, the combination with the log-carriage having a longitudinally-movable head-block, of a head-block shifter consisting of a rod or bar secured between two braces which are pivoted to the side of the carriagetrack so that said rod can be swung into position to engage and stop said head-block or 4:. In a sawmill, the combination with the log-carriage having a' longitudinally-movable head-block, of a head-block shifter consisting of a stop adapted to be moved into and out of the path of travel of the head-block, and connections for moving and holding said stop in desired position, substantially as described.

5. In a sawmill, the combination with the log-carriage having a longitudinally-movable head-block, of a head-block shifter comprising a stop movable transversely to the carriage and capable of being thrown into or out of the path of travel of the head-block, and a lever and connections whereby said stop can be moved and held in desired position, substantially as described.

In testimony whereof I aflix my signature in presence of two witnesses. I

- JOHN T. SIMPSON. Witnesses:

Jon H. KoLLooK, A. S. HENDERSON. 

